Tank Relining – Cooling Tower Re-coating
As part of our clients proactive water hygiene regime they had identified corrosion and coating failure in one of their cooling towers which could harbour aquatic micro organisms such as legionella.
We initially prepared the cooling tower internals for relining by method of abrasive blasting to remove loose and unsound coatings as well as to raise a profile on any well adhered coatings. Any exposed steel was prepared to SA2.5. Following blasting the cooling tower was thoroughly cleaned to ensure excellent adhesion of the new lining.
Once clean all seams and joints were sealed using WRAS approved polyurethane sealant applied using mastic guns.
Because of the vibration present in cooling towers it is essential to use a lining system which has a degree of flexibility. For this reason we selected the flexible polyurethane Acothane from Spencer Coatings. Epoxy coatings of GRP Linings will usually crack as a result of the vibration present, which will in turn provide a habitat for aquatic micro organisms.
Separate stripe coats were applied to all nuts, bolts, angles and edges as per good coating practice to ensure full coating film build in these weak spots.
Acothane was applied in two coats of contrasting colour to a dry film thickness of 1000 microns .
When cured the new lining was tested for pin holing using a DC holiday spark tester.